Earth-moving machines, particularly tracked vehicles such as excavators, have reached proportions such that it is necessary to provide access steps to enable the operator or repairman to reach the operator's cab or the engine compartment. Location of such steps in tracked vehicles is particularly difficult as the construction of the tracks requires the step to be mounted outwardly of the track frame. In so mounting the step outwardly of the track frame, it has been found that rigid steps are easily broken when the vehicle is moved from one position to another as the step contacts an obstruction.
A step or ladder to mount such a vehicle must provide a relatively rigid footrest as the operator or repairman places his weight upon the step, therefore deflection in a downward direction relative to the vehicle frame must be limited. Various types of retracting ladders have been designed for large construction vehicles; however, such a ladder is inappropriate in a tracked vehicle where it is necessary to locate the mounting step on the track frame, as retraction of the ladder into the track frame could interfere with the rotating parts therein. Steps of a type which hang below the vehicle frame in the form of a U-shaped member have also been designed, such steps providing deflection both longitudinally of the vehicle frame and laterally of the vehicle frame. However, a step of this design is also generally inappropriate for tracked vehicles. Hanging a U-shaped member from the track frame is inadvisable for two reasons. First, deflection of such a step inwardly while the vehicle is moving could cause serious interference with the moving members of the track assembly. Secondly, to locate such a step below the track frame would be of no advantage, as the footrest portion of a hanging step would then be in close proximity to the ground level. Furthermore, insertion of a foot of the operator in such a hanging step could possibly result in the operator's foot becoming entangled with the moving parts of the tracked vehicle.